Start here:

1. Have your students download a QR scanner.
2. Generate QR codes - there are many generators out there. Here are a couple of free ones:

3. Choose the kind of information you want to convert to QR code and enter it.
4. Print your QR code or use them on your blog, website,

Tips and Tricks:

Use a URL shortener like bit.ly or tiny.url - This is optional, but will make codes less complicated
Test your QR code.
Print your QR codes - at least one inch square with a white border.
Use them on a flat surface.